https://learn.microsoft.com/en-us/dotnet/api/system.web.ui.webcontrols.button.commandname?view=netframework-4.8.1&redirectedfrom=MSDN
Button.CommandName Property (System.Web.UI.WebControls) | Microsoft Learn
Gets or sets the command name associated with the Button control that is passed to the Command event.
property systemweb uibuttonmicrosoftlearn